Image forming apparatus and image forming method using patch images

Abstract

An image forming apparatus includes an image carrier that holds a toner-image; an intermediate transfer member onto which the toner-image that has been held on the image carrier is transferred; a transfer unit that transfers onto a recording medium the toner-image that has been transferred onto the intermediate transfer member, the transfer unit transferring thereon a color-toner-image for checking toner-image, which has been formed in a non-image forming region on the intermediate transfer member; an application unit that applies an adhesion force reducing agent to a surface of the transfer unit before the color-toner-image for checking formed on the intermediate transfer member passes through the transfer unit, the adhesion force reducing agent reducing adhesion force to the transfer unit of the color-toner-image for checking; and a cleaning unit that removes the color-toner-image for checking that has been transferred onto the transfer unit and the adhesion force reducing agent.

1. An image forming apparatus comprising:
 an image carrier that holds a toner image; 
 an intermediate transfer member onto which the toner image that has been held on the image carrier is transferred; 
 a transfer unit that transfers onto a recording medium the toner image that has been transferred onto the intermediate transfer member, the transfer unit transferring thereon a color toner image for checking the toner image, which has been formed in a non-image forming region on the intermediate transfer member; 
 an application unit that applies an adhesion force reducing agent to a surface of the transfer unit before the color toner image for checking the toner image formed on the intermediate transfer member passes through the transfer unit such that the color toner image for checking the toner image is transferred onto the adhesion force reducing agent applied on the surface of the transfer unit, the adhesion force reducing agent reducing adhesion force to the transfer unit of the color toner image for checking the toner image; and 
 a cleaning unit that removes the color toner image for checking the toner image that has been transferred onto the transfer unit and the adhesion force reducing agent. 
 
   
   
     2. The image forming apparatus of  claim 1 , wherein the application unit applies the adhesion force reducing agent to the intermediate transfer member at a region that is at a downstream side, in a moving direction of the intermediate transfer member, with respect to a region to which the color toner image for checking the toner image is transferred. 
   
   
     3. The image forming apparatus of  claim 1 , wherein the application unit directly applies the adhesion force reducing agent to the transfer unit at a region to which the color toner image for checking the toner image is to be transferred. 
   
   
     4. The image forming apparatus of  claim 1 , wherein the transfer unit includes a separation belt that wraps around a transfer roll that transfers the toner image on the intermediate transfer member onto the recording medium, the separation belt separates the recording medium from the intermediate transfer member, and on the separation belt, color toner image for checking the toner image is transferred onto the adhesion force reducing agent. 
   
   
     5. The image forming apparatus of  claim 1 , wherein the transfer unit includes a transfer roll that transfers the toner image on the intermediate transfer member onto the recording medium, and the color toner image for checking the toner image is transferred onto the transfer roll. 
   
   
     6. The image forming apparatus of  claim 1 , wherein the cleaning unit includes a conductive cleaning member. 
   
   
     7. The image forming apparatus of  claim 1 , wherein the adhesion force reducing agent is one of a transparent toner or a white toner. 
   
   
     8. The image forming apparatus of  claim 7 , wherein a bias of the same polarity as that of the transparent toner or the white toner is applied to the cleaning unit up until the time when all of the color toner image for checking the toner image is transferred onto the transparent toner or onto the white toner. 
   
   
     9. The image forming apparatus of  claim 7 , wherein when all of the color toner image for checking the toner image is transferred onto the transparent toner or onto the white toner, a bias of reverse polarity with respect to that of the color toner image for checking the toner image is applied to the cleaning unit. 
   
   
     10. The image forming apparatus of  claim 2 , wherein the application unit is disposed at an upstream side, in the moving direction of the intermediate transfer member, with respect to the transfer unit such that the adhesion force reducing agent is transferred from the intermediate transfer member to the transfer unit. 
   
   
     11. The image forming apparatus of  claim 3 , wherein the application unit is disposed in the vicinity of the transfer unit such that the application unit directly applies the adhesion force reducing agent to the transfer unit. 
   
   
     12. An image forming method comprising:
 transferring a toner image that has been held on an image carrier onto an intermediate transfer member; 
 transferring onto a recording medium the toner image that has been transferred onto the intermediate transfer member; 
 transferring onto a transfer unit a color toner image for checking the toner image which has been formed in a non-image forming region on the intermediate transfer member; 
 applying an adhesion force reducing agent to a surface of the transfer unit before the color toner image for checking the toner image formed on the intermediate transfer member passes through the transfer unit, such that the color toner image for checking the toner image is transferred onto the adhesion force reducing agent applied on the surface of the transfer unit, the adhesion force reducing agent reducing adhesion force to the transfer unit of the color toner image for checking the toner image; and 
 removing the color toner image for checking the toner image that has been transferred onto the transfer unit and the adhesion force reducing agent. 
 
   
   
     13. The image forming method of  claim 12 , wherein the adhesion force reducing agent is applied to the intermediate transfer member at a region that is at a downstream side, in a moving direction of the intermediate transfer member, with respect to a region to which the color toner image for checking the toner image is transferred. 
   
   
     14. The image forming method of  claim 12 , wherein the adhesion force reducing agent is directly applied to the transfer unit at a region to which the color toner image for checking the toner image is to be transferred. 
   
   
     15. The image forming method of  claim 12 , wherein the transfer unit includes a separation belt that wraps around a transfer roll that transfers the toner image on the intermediate transfer member onto the recording medium, the separation belt separates the recording medium from the intermediate transfer member, and on the separation belt, color toner image for checking the toner image is transferred onto the adhesion force reducing agent. 
   
   
     16. The image forming method of  claim 12 , wherein the transfer unit includes a transfer roll that transfers the toner image on the intermediate transfer member onto the recording medium, and the color toner image for checking the toner image is transferred onto the transfer roll. 
   
   
     17. The image forming method of  claim 12 , wherein a cleaning unit removes the color toner image for checking the toner image and the adhesion force reducing agent, and includes a conductive cleaning member. 
   
   
     18. The image forming method of  claim 12 , wherein the adhesion force reducing agent is one of a transparent toner or a white toner. 
   
   
     19. The image forming method of  claim 18 , wherein a bias of the same polarity as that of the transparent toner or the white toner is applied to the cleaning unit up until the time when all of the color toner image for checking the toner image is transferred onto the transparent toner or onto the white toner. 
   
   
     20. The image forming method of  claim 18 , wherein when all of the color toner image for checking the toner image is transferred onto the transparent toner or onto the white toner, a bias of reverse polarity with respect to that of the color toner image for checking the toner image is applied to the cleaning unit.